:glass tty: /glas T-T-Y/ or /glas ti'tee/ n. A terminal that
has a display screen but which, because of hardware or software
limitations, behaves like a teletype or some other printing
terminal, thereby combining the disadvantages of both: like a
printing terminal, it can't do fancy display hacks, and like a
display terminal, it doesn't produce hard copy. An example is the
early `dumb' version of Lear-Siegler ADM 3 (without cursor
control). See {tube}, {tty}; compare {dumb terminal}, {smart
terminal}. See "{TV Typewriters}" (appendix A) for an
interesting true story about a glass tty.
-- The AI Hackers Dictionary
munching squares: n. A {display hack} dating back to the PDP-1
(ca. 1962, reportedly discovered by Jackson Wright), which employs
a trivial computation (repeatedly plotting the graph Y = X XOR T
for successive values of T --- see {HAKMEM} items 146--148) to
produce an impressive display of moving and growing squares that
devour the screen....